1 - Principles of chemistry

3 properties of solids

strong forces of attraction, vibrate, regular lattice

2 properties of liquids

weak forces of attraction, move freely

2 properties of gases

very weak forces of attraction, move very freely

what happens to particles during melting, boiling and sublimation?

move faster, weakening the forces

what happens to particles during condensing, freezing and sublimation?

move slower so get closer

what is boiling?

all particles move at the same speed so all turn into gas at the same time

what is evaporation?

some particles move faster so they turn into gas first

experiment of dilution

crystals of potassium manganate in water

experiment of diffusion

bromine gas and air

what is a solvent?

The liquid in which the solute dissolves

what is a solute?

A substance that is dissolved in a solution

what is a solution?

the mixture formed when a solute dissolves in a solvent

what is a saturated solution?

a solution where there is an equilibrium between the solution and its solute

What does soluble mean?

able to be dissolved

what does insoluble mean?

unable to dissolve

as temperature increases, gases become .......... soluble

less

as temperature increases, solids become ........... soluble

more

as pressure increases, gases become ........... soluble

more

What do solubility curves show?

solubility in g per 100g of water against temperature

what is an element?

a substance of only one atom, which cannot be split

what is a compound?

pure substance of two or more elements chemically combined, which cannot be separated physically

what is a mixture?

a combination of two or more elements not chemically combined, which can be separated physically

What are pure substances?

fixed melting and boiling points

what are mixtures?

melt and boil over a range of temperatures

what is simple distillation used for?

Separating a liquid from a solution

simple distillation can only be used to separate substances with ........ ................... boiling points

very different

what is fractional distillation used for?

separating a mixture of liquids

what is filtration used for?

Separating an insoluble solid from a liquid

What is the retention factor in chromatography?

distance travelled by dye/distance travelled by solvent

what is crystallisation used for?

Separating a soluble solid from a solution

what is an atom?

Smallest particle of an element

what is a molecule?

smallest part of an element or compound that can exist independently

what does the nucleus contain?

protons and neutrons

where is the main mass of an atom?

nucleus

mass and charge of proton

1, +1

mass and charge of neutron

1, 0

mass and charge of electron

1/2000, -1

if an atom is neutral, number of ............ = number of .............

protons, electrons

what is relative atomic mass?

average mass of the isotopes of an element

how do calculate relative atomic mass?

number of neutrons (mass number - atomic number)

what are molecules held together by?

covalent bonds

what are isotopes?

atoms of the same element with the same number of protons but different numbers of neutrons

what is the period?

horizontal row showing number of shells

what is the group?

column showing number of outer electrons

are metals alkaline or acidic?

alkaline

are non-metals alkaline or acidic?

acidic

what are the chemical properties of elements in the same group like?

similar

the noble gases are ............. because they have a ........ ............. ............

unreactive, full outer shell

what are moles?

amount of a substance

moles =

Mass / Mr

how do you calculate reacting masses?

find moles, ratio, moles of other substance, apply this answer to find mass

what is percentage yield?

The amount of product you get

percentage yield =

actual yield/theoretical yield x 100

what is the empirical formula?

The simplest whole number ratio of atoms of each element in a compound

what is the molecular formula?

exact number of atoms of each element in a compound

what is ionic bonding?

bond between a metal and non-metal with strong electrostatic forces of attraction between oppositely charged ions

ionically bonded substances have ........... melting and boiling points

high

charge of group 1

+1

charge of group 2

+2

charge of group 3

+3

charge of group 5

3-

charge of group 6

2-

charge of group 7

1-

silver ion

Ag+

copper charge

Cu2+

iron charge

Fe2+

lead charge

Pb2+

zinc charge

Zn2+

hydroxide charge

OH-

ammonium charge

NH4+

carbonate charge

CO32-

nitrate charge

NO3-

sulphate charge

SO42-

what are giant ionic lattices?

giant three-dimensional lattice structure held together by the strong attraction between oppositely charged ions

do giant ionic lattices have a high or low melting and boiling point?

high

Can ionic compounds conduct electricity?

when they are not solids

what is covalent bonding?

the bond between two non-metals formed by a shared pair of electrons between the atoms

what are electrostatic attractions in?

covalent bonding

what are electrostatic attractions?

the strong attraction between the shared pair of electrons and the nuclei involved

what is a simple molecular structure?

consists of molecules in which the atoms are joined by strong covalent bonds

Why do simple molecules have low melting points and boiling points?

they have very strong covalent bonds between atoms but weak intermolecular forces

what is relative molecular mass?

total relative atomic masses form all atoms shown in its chemical formula

which is giant covalent structure?

contains lots of non-metal atoms, each joined to adjacent atoms by covalent bonds forming a giant lattice

giant covalent structures are.....

solids

giant covalent structures have .......... melting and boiling points because ............

high, strong covalent bonds

what are allotropes?

different atomic and molecular arrangements of the same element

why is diamond hard?

each carbon atom is joined to 4 other carbon atoms with strong covalent bonds

Why does diamond have a high melting point?

giant covalent structure means that there are lots of strong covalent bonds

Why does diamond not conduct electricity?

all outer shell electrons are used in covalent bonds, there are no delocalised electrons to conduct electricity

2 uses of diamond

cutting tools, jewellery

why is graphite soft and slippery?

made up of layers of carbon atoms held together which have weak forces of attraction between them

Why does graphite have a high melting point?

each carbon atom has strong covalent bonds with the three other carbon atoms in a giant covalent structure

Why does graphite conduct electricity?

only three electrons are used in the covalent bonds, the fourth electron is delocalised and free to move

2 uses of graphite

lubricant, electrodes for electrolysis

why is C60 fullerene soft?

each carbon atom is joined to three others so there are weak intermolecular forces between the molecules

why does C60 fullerene have low boiling points?

each carbon atom is joined to three others so there are weak intermolecular forces between the molecules

why do covalent compounds not conduct electricity?

they don't have any delocalised electrons that are free to move and conduct charge

what is a metallic lattice?

giant three-dimensional lattice structure of positive ions surrounds by a sea of delocalised electrons

How are metal atoms held together?

metallic bonding

what is the sea of delocalised electrons in a metallic lattice?

when the metal atoms lose electrons to become ions